Make examples' shebang use target tcc bindir path

Use @BINDIR@ in shebang of examples to put the right path on the target
system. That is, use #!/usr/local/bin/tcc if tcc is installed in /usr/local/bin
and #!/usr/bin/tcc if tcc is installed in /usr/bin/tcc.

examples/ex1.c.template

@@ -0,0 +1,8 @@
+#! @BINDIR@/tcc -run
+#include <tcclib.h>
+
+int main()
+{
+    printf("Hello World\n");
+    return 0;
+}